Phenol is an important product in the chemical industry and is useful in, for example, the production of phenolic resins, bisphenol A, ε-caprolactam, adipic acid, plasticizers, and polymers, such as nylon-6.
Currently, a common route for the production of phenol is the Hock process via cumene. This is a three-step process in which the first step involves alkylation of benzene with propylene in the presence of an acidic catalyst to produce cumene. The second step is oxidation, preferably aerobic oxidation, of cumene to the corresponding cumene hydroperoxide. The third step is the cleavage of the cumene hydroperoxide in the presence of heterogeneous or homogeneous catalysts into equimolar amounts of phenol and acetone, a co-product. However, the world demand for phenol is growing more rapidly than that for the acetone co-product. This imbalance depresses the value of the co-product reducing the economic benefits of the Hock process.
Thus, a process that co-produces higher ketones, rather than acetone, may be an attractive alternative route to the production of phenol. In addition, there is a growing market for cyclohexanone, which is used as an industrial solvent, as an activator in oxidation reactions and in the production of adipic acid, cyclohexanone resins, cyclohexanone oxime, caprolactam, and nylon-6.
As it has been recently disclosed, phenol and cyclohexanone can be co-produced by a novel process in which cyclohexylbenzene is oxidized to obtain cyclohexylbenzene hydroperoxide, which, in turn, is decomposed in the presence of an acid catalyst to the desired phenol and cyclohexanone in a cleavage process.
The chemistries in each step of the production of phenol and cyclohexanone from cyclohexylbenzene are very different from those of the Hock process for producing phenol and acetone from cumene.
For example, the cleavage reaction of cyclohexylbenzene hydroperoxide is more complex than the cleavage reaction of cumene hydroperoxide. More different side reactions may occur, significantly reducing the yield of phenol and/or cyclohexanone. Thus, novel cleavage process and equipment are desired for the cleavage reaction of cyclohexylbenzene hydroperoxide.